Expansion joint construction system

ABSTRACT

The present invention relates generally to an improved expansion joint construction and a method for creating an expansion joint between adjacent roadway slabs. The invention relates specifically to the use of an epoxy blend having improved set times that can be applied in cold weather.

FIELD OF THE INVENTION

The present invention relates generally to an improved expansion joint construction system and a method for creating an expansion joint for bridges, roadways, parking structures and the like wherein adjacent slabs are subject to movement and a flexible seal is required in the expansion gap between adjacent slabs. The invention relates specifically to an expansion joint system which provides a high strength, impact resistant and semi-flexible joint nose, allows various liquid or preformed seals to be used in the gap to absorb movement, can be applied in cold weather, and sets in a short amount of time.

BACKGROUND OF THE INVENTION

Roadways, bridges, and parking structures are typically built of sections or slabs arranged with expansion gaps between adjacent sections to account for the natural expansion and contraction of the sections as temperatures change, and vertical movement caused by vehicular traffic. The expansion gaps need to be sealed to prevent water from getting beneath the sections and leading to rusting of steel substructures, heaving in freezing temperatures, or otherwise deteriorating components of the slabs. Seals are also needed to prevent corrosives, such as salt, and other debris from getting in the joint and causing damage to the sections. When gaps or seals are damaged, or have deteriorated over time, it is necessary to repair the expansion joint and create a new seal to prevent any additional damage. When repairing expansion gaps it is advantageous to be able to complete the repair process as quickly as possible to minimize the time that traffic must remain off the expansion gap.

Various materials and systems have been implemented to provide flexible seals that can move with the movement of adjacent slabs and prevent water and/or debris from getting into the expansion gap and causing damage. For a discussion of prior systems see Cathey et al. (U.S. Pat. No. 5,190,395).

In new roadway, bridge, or parking structure construction, time may not be a critical factor in the installation of a joint seal. However, in remedial applications, time is a critical factor, and repair and roadway down time should be minimized so that vehicle traffic can return. However, if traffic is returned before the nosings and seal materials are set, additional damage may be done to the nosings and seal, significantly diminishing the usable life of the seal. In addition, in colder weather prior systems generally take longer to set and may require additional steps and components to install, effectively making the systems commercially infeasible when temperatures drop below 40 degrees Fahrenheit. For example, at 40 degrees Fahrenheit a prior system may take around nine hours to cure or set. Some systems have added supplemental heat and used additives to accelerate the set time, however, even with these additional steps, prior systems do not set as quickly as the present invention and add to the expense of installation. For example, at 40 degrees Fahrenheit a prior system may mix in an accelerator agent and provide supplemental heat and still may take around three and a half hours to cure or set. Such a system would, therefore, not be recommended for installation in colder temperatures.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a joint construction system that sets quickly to minimize down time.

It is a further object of the present invention to provide a joint construction system that can set quickly in cold temperatures.

It is a further object of the present invention to provide a joint construction system that can set quickly in cold temperatures without the need to include additives for accelerating the set time.

It is a further object of the present invention to provide a joint construction system that can set quickly in cold temperatures without the need to add supplemental heat during the installation process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 through 3 illustrate sectional views showing an installation sequence of an expansion joint system of the present invention; and

FIGS. 4 through 6 illustrate sectional views showing an installation sequence of an expansion joint system of the present invention in a remedial application having concrete slabs with an asphalt overlay.

DETAILED DESCRIPTION

The figures and the following description describe two examples of the installation sequence of an expansion joint system of the present invention. As one having skill in the art will recognize, the installation sequence may be varied, may be applied to new constructions or may be applied in other remedial applications and remains within the scope and spirit of the invention. In addition, the installation sequence may be applied in a number of uses, including but not limited to roadways, bridges, and parking structures.

FIG. 1 shows sectional views of a pair of adjacent slabs 12 and 14. In between slab 12 and slab 14 is an expansion gap to permit necessary movement of the slabs. Recesses 16 and 18 are shown in each adjacent slab 12 and 14. The bases of recesses 16 and 18 are approximately parallel to the surface of the roadway 20 and 22. The sidewalls of recesses 16 and 18 are approximately parallel to the walls of slab 12 and 14 that define the expansion gap and approximately perpendicular to the surface of roadway 20 and 22.

This is the general starting point for the installation sequence between two adjacent concrete slabs. One can arrive at this point through a variety of ways. In new construction the slabs may be created with the appropriate recesses and placed such that they define an appropriate expansion gap. In remedial applications, a prior seal may need to be removed and the recesses cleared of prior header material or cut out of the concrete through means known in the art.

Once recesses 16 and 18 are defined in slabs 12 and 14, they should be prepared for the installation sequence. Preparation of the recess requires the surfaces of the recess to be cleaned and dried sufficiently to allow the mortar to adhere to the recess surfaces. In a preferred embodiment, recesses 16 and 18 will be thoroughly cleaned to remove all rust, corrosion, and debris and will be fully dried. For example, one may first sandblast the recess to remove rust and corrosion. Then the sand and other debris can be removed by blowing the recesses with oil free compressed air. As one having skill in the art will recognize, any level of preparation that allows the mortar to adhere to the recess surfaces falls within the scope and spirit of the invention.

After recesses 16 and 18 have been prepared, temporary form 24 is installed in the gap between slab 12 and slab 14 with the top flush with or above the surface of roadway 20 and 22. Temporary form 24 is preferably made of extruded polystyrene, but may be made of other lightweight materials. In some embodiments, other materials may be attached to temporary for 24 to facilitate the removal of the form later in the process.

Prior to filling recesses 16 and 18, the mortar is mixed. The mortar must be an epoxy-urethane blend that can be applied in various temperatures, including temperatures under 40 degrees, and set in less than two hours. An example of one such mortar is Silspec 1000 from Silicone Specialties, Inc. In a preferred embodiment the epoxy-urethane blend, when set, has a tensile strength of approximately 1500 pounds per square inch (psi), elongation properties of approximately 30% to 40%, a compressive strength of approximately 3500 psi, and a Shore D hardness of approximately 60 to 70. In a preferred embodiment, the mortar is kept in two components that are mixed to create the epoxy-urethane blend prior to installing the mortar. In a preferred embodiment, after the components of the mortar are mixed, sand and other aggregate such as crushed stone or flint is mixed with the mortar. As one having skill in the art will recognize the mortar does not need to include the sand or other aggregate to remain within the scope and spirit of the present invention.

Once the mortar and any desired aggregate are mixed together, it is poured into recesses 16 and 18. FIG. 2 shows mortar mixture in recesses 16 and 18. The mortar mixture is poured to fill recesses 16 and 18 near or up to the surface of roadway 20 and 22. Unlike prior systems, there is no need to provide a primer layer between the mortar and the concrete, however, the inclusion of a primer step remains within the scope and spirit of the present invention. In a preferred embodiment, once the mortar mixture is poured into recesses 16 and 18, it is compacted.

The mortar mixture is then allowed to set and/or cure throughout to create nosings 26 and 28. In 40 degree Fahrenheit weather, the mortar mixture can set in approximately one hour. In 10 degree Fahrenheit weather, the mortar mixture can set in approximately one and a half hours. If the mortar mixture is only filled to near the level of the roadway surface, a separate layer of mortar that corresponds to the finish of roadway 20 and 22 may be applied up to the level of the surface of roadway 20 and 22. As one skilled in the art will recognize, the additional layer of mortar is not necessary and remains within the scope and spirit of the invention.

Once nosings 26 and 28 are set, temporary form 24 is removed as is illustrated by the dotted lines in FIG. 2. In a preferred embodiment, the edges of nosings 26 and 28 may be beveled using a grinder or other tool. As one having skill in the art will recognize, the edges may be beveled in other ways or the beveling step may be skipped and remain within the scope and spirit of the present invention.

Next, a seal is created between slabs 12 and 14, preferably at nosings 26 and 28. In this embodiment a seal is created by inserting and wedging backer rod 32 in the gap between the nosings as shown in FIG. 3. Backer rod 32 may be made of a closed cell polyethelene foam or other similar materials. Backer rod 32 is used as a shelf to hold silicone sealant 30 in place while silicone sealant 30 is applied in liquid form into the gap and on top of backer rod 32. As one having skill in the art will recognize, any temporary or permanent backing may be used in place of backer rod 32 to provide a base for applying the seal and remains within the scope and spirit of the invention. In addition, one having skill in the art will recognize that other seals such as compression seals, pre-compressed foams, closed cell foam seals, pre-formed silicone profile seals, pressurized compression seals, liquid applied seals, liquid applied joint sealants, or other seals may be used in place of or in conjunction with the described seal and remain within the scope and spirit of the invention.

FIGS. 4 through 6 illustrate the use of the present expansion joint system to install an expansion joint in a concrete slabs 40 and 42 which have been overlaid with asphalt overlay 48 and 50. FIG. 4 shows sectional views of a pair of adjacent slabs 40 and 42 with asphalt overlay 48 and 50 on top of slabs 40 and 42 respectively. In between slab 40 and slab 42 is an expansion gap to permit necessary movement of the slabs. In this embodiment, recesses 44 and 46 are shown as an area of the roadway adjacent to the expansion gap where asphalt overlays 48 and 50 are missing above each adjacent slab 40 and 42. The bases of recesses 44 and 46 are the top surfaces of slab 40 and slab 42. The sidewalls of recesses 44 and 46 are approximately parallel to the walls of slab 40 and 42 that define the expansion gap and approximately perpendicular to the surface of the surface of asphalt overlays 48 and 50.

As discussed above, one can arrive at this point through a variety of ways. In a remedial application with an asphalt overlay, sections of asphalt overlay 48 and 50 may cut out down to the surface of concrete slabs 40 and 42 and removed.

Once recesses 44 and 46 are defined, they should be prepared for the installation sequence. As discussed above, preparation of the recess requires the surfaces of the recess to be cleaned and dried sufficiently to allow the mortar to adhere to the recess surfaces. In a preferred embodiment, one may first sandblast the recess to remove rust and corrosion, and then blow recesses 44 and 46 with oil free compressed air to remove the sand and other debris. After recesses 44 and 46 have been prepared, temporary form 52 is installed in the gap between slab 40 and slab 42 with the top flush with or above the surface of asphalt overlay 48 and 50.

Prior to filling recesses 44 and 46, the mortar is mixed. As discussed above, the mortar must be an epoxy-urethane blend that can be applied in various temperatures, including temperatures under 40 degrees, and set in less than two hours. An example of one such mortar is Silspec 1000 from Silicone Specialties, Inc. In a preferred embodiment the epoxy-urethane blend, when set, has a tensile strength of approximately 1500 pounds per square inch (psi), elongation properties of approximately 30% to 40%, a compressive strength of approximately 3500 psi, and a Shore D hardness of approximately 60 to 70. In a preferred embodiment, the mortar is kept in two components that are mixed to create the epoxy-urethane blend prior to installing the mortar. In a preferred embodiment, after the components of the mortar are mixed, sand and other aggregate such as crushed stone or flint is mixed with the mortar.

Once the mortar and any desired aggregate are mixed together, it is poured into recesses 44 and 46. FIG. 5 shows mortar mixture in recesses 44 and 46. Mortar mixture fills recesses 44 and 46 up to the surface of asphalt overlay 48 and 50. Unlike prior systems, there is no need to provide a primer layer between the mortar and the concrete, however, the inclusion of a primer step remains within the scope and spirit of the present invention. In a preferred embodiment, once the mortar mixture is poured into recesses 44 and 46, it is compacted.

Mortar mixture is then allowed to set and/or cure throughout to create nosings 54 and 56. In 40 degree Fahrenheit weather, the mortar mixture can set in approximately one hour. In 10 degree Fahrenheit weather, the mortar mixture can set in approximately one and a half hours. Once nosings 54 and 56 are set, temporary form 52 is removed as is illustrated by the dotted lines in FIG. 5. In a preferred embodiment, the edges of nosings 54 and 56 may be beveled using a grinder or other tool.

Next, a seal is created between adjacent slabs 40 and 42 at nosings 54 and 56. In this embodiment a seal is created by inserting and wedging backer rod 60 in the gap between the nosings as shown in FIG. 6. Backer rod 60 may be made of a closed cell polyethylene foam rubber or other similar materials. Backer rod 60 is used as a shelf to hold silicone sealant 58 in place while silicone sealant 58 is applied in liquid form into the gap and on top of backer rod 60. As one having skill in the art will recognize, other seals such as compression seals, pre-compressed foams, closed cell foam seals, pre-formed silicone profile seals, pressurized compression seals, liquid applied seals, liquid applied joint sealants, or other seals may be used in place of or in conjunction with the described seal and remain within the scope and spirit of the invention.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

1. A method for creating an expansion joint between adjacent structures having an expansion gap there between comprising the steps of: a) preparing at least one recess along an edge of at least one of said adjacent structures; b) installing at least one form to define at least one nosing area; and c) installing a mortar into said at least one nosing area, wherein said mortar is an epoxy-urethane blend that cures in less than two hours.
 2. The method of claim 1 further comprising the step of installing a seal spanning said expansion gap.
 3. The method of claim 2 wherein said seal is selected from a group consisting of compression seals, pre-compressed foams, closed cell foam seals, pre-formed silicone profile seals, liquid applied joint sealants, liquid applied seals, and pressurized compression seals.
 4. The method of claim 2 wherein the step of installing a seal further comprises the step of removing said at least one form.
 5. The method of claim 2 wherein the step of installing a seal further comprises the steps of inserting a backing; and applying a seal on top of said backing.
 6. The method of claim 1 further comprising the step of cutting said at least one recess into at least one of said adjacent structures.
 7. The method of claim 1 wherein the step of installing a mortar further comprises the steps of: a) combining said mortar with at least one aggregate to create a mortar mixture; and b) pouring said mortar mixture into said at least one nosing area.
 8. The method of claim 7 wherein said aggregate is stone.
 9. The method of claim 7 wherein said aggregate is sand.
 10. The method of claim 7 wherein said aggregate is a combination of sand and stone.
 11. The method of claim 1 wherein said mortar has a tensile strength of approximately 1500 pounds per square inch when cured.
 12. The method of claim 1 wherein said mortar has a compressive strength of approximately 3500 pounds per square inch when cured.
 13. The method of claim 1 wherein said mortar has elongation properties in the range of approximately 30 to 40 percent when cured.
 14. The method of claim 1 wherein said mortar has a Shore D hardness in the range of approximately 60 to 70 when cured.
 15. The method of claim 1 wherein said mortar is Silspec
 1000. 16. The method of claim 1 wherein said mortar may be applied in temperatures below 70 degrees Fahrenheit.
 17. The method of claim 1 wherein said mortar may be applied in temperatures below 40 degrees Fahrenheit.
 18. The method of claim 1 wherein said mortar may be applied in temperatures below 20 degrees Fahrenheit.
 19. The method of claim 1 wherein said mortar may be applied in temperatures between 70 degrees Fahrenheit and 0 degrees Fahrenheit.
 20. A method for creating an expansion joint between adjacent structures having an expansion gap there between comprising the steps of: a) preparing a first recess along an edge of a first structure of said adjacent structures; b) preparing a second recess along an edge of a second structure of said adjacent structures, wherein said first recess is adjacent to said second recess and said expansion gap is there between; c) installing at least one form to define at least two adjacent nosing areas at said first recess and said second recess; and d) installing a mortar into each of said at least two adjacent nosing areas, wherein said mortar is an epoxy-urethane blend that cures in less than two hours.
 21. The method of claim 20 further comprising the step of installing a seal spanning said expansion gap.
 22. The method of claim 21 wherein said seal is selected from a group consisting of compression seals, pre-compressed foams, closed cell foam seals, pre-formed silicone profile seals, liquid applied joint sealants, liquid applied seals, and pressurized compression seals.
 23. The method of claim 21 wherein the step of installing a seal further comprises the step of removing said at least one form.
 24. The method of claim 21 wherein the step of installing a seal further comprises the steps of inserting a backing; and applying a seal on top of said backing.
 25. The method of claim 20 further comprising the step of cutting said first recess into said first structure.
 26. The method of claim 25 further comprising the step of cutting said second recess into said second structure.
 27. The method of claim 20 wherein the step of installing a mortar further comprises the steps of: a) combining said mortar with at least one aggregate to create a mortar mixture; and b) pouring said mortar mixture into said nosing areas.
 28. The method of claim 27 wherein said aggregate is stone.
 29. The method of claim 27 wherein said aggregate is sand.
 30. The method of claim 27 wherein said aggregate is a combination of sand and stone.
 31. The method of claim 20 wherein said mortar has a tensile strength of approximately 1500 pounds per square inch when cured.
 32. The method of claim 20 wherein said mortar has a compressive strength of approximately 3500 pounds per square inch when cured.
 33. The method of claim 20 wherein said mortar has elongation properties in the range of approximately 30 to 40 percent when cured.
 34. The method of claim 20 wherein said mortar has a Shore D hardness in the range of approximately 60 to 70 when cured.
 35. The method of claim 20 wherein said mortar is Silspec
 1000. 36. The method of claim 20 wherein said mortar may be applied in temperatures below 70 degrees Fahrenheit.
 37. The method of claim 20 wherein said mortar may be applied in temperatures below 40 degrees Fahrenheit.
 38. The method of claim 20 wherein said mortar may be applied in temperatures below 20 degrees Fahrenheit.
 39. The method of claim 20 wherein said mortar may be applied in temperatures between 70 degrees Fahrenheit and 0 degrees Fahrenheit. 